US20120026688A1 - Axial fan and electronic device including the same - Google Patents
Axial fan and electronic device including the same Download PDFInfo
- Publication number
- US20120026688A1 US20120026688A1 US13/185,523 US201113185523A US2012026688A1 US 20120026688 A1 US20120026688 A1 US 20120026688A1 US 201113185523 A US201113185523 A US 201113185523A US 2012026688 A1 US2012026688 A1 US 2012026688A1
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- United States
- Prior art keywords
- side wall
- flange
- axial fan
- portions
- slits
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/58—Cooling; Heating; Diminishing heat transfer
- F04D29/582—Cooling; Heating; Diminishing heat transfer specially adapted for elastic fluid pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
- F04D25/0606—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump
- F04D25/0613—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump the electric motor being of the inside-out type, i.e. the rotor is arranged radially outside a central stator
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/52—Casings; Connections of working fluid for axial pumps
- F04D29/522—Casings; Connections of working fluid for axial pumps especially adapted for elastic fluid pumps
- F04D29/526—Details of the casing section radially opposing blade tips
Definitions
- the present invention relates to an axial fan and an electronic device including the same.
- Axial fans whose housings include slits have been known.
- World Intellectual Property Organization Publication No. 2009/057063 discloses one such conventional axial fan.
- This conventional axial fan includes an impeller in which a plurality of blades are arranged in a circumferential direction about a central axis, and a housing (i.e., a wind tunnel portion) arranged radially outward of the impeller to surround the impeller.
- the housing includes a plurality of slits that are arranged in the circumferential direction and arranged to extend through the housing from an inner circumferential surface to an outer circumferential surface thereof.
- the conventional axial fan as described above is often used as a cooling fan for an electronic device or the like, and is often attached to an exhaust duct provided in a casing of an electronic device or the like to define an air channel in the casing.
- the axial fan is sometimes attached to the duct such that an outer circumference of the axial fan is covered by a surface of the duct depending on the shape of the duct.
- the slits will be covered by the presence of the surface of the duct on the outside of the axial fan.
- An axial fan includes an impeller arranged to rotate about a central axis, and including a plurality of blades centered on the central axis, arranged to project radially outward, and arranged in a circumferential direction; and a housing including a side wall arranged to have openings at both axial ends thereof and arranged to surround an outer circumference of the impeller, and a substantially square or substantially rectangular flange arranged to project radially outward from an outer circumferential surface of the side wall.
- the side wall preferably includes an opening end at the axial end thereof on an inlet side and another opening end at the axial end thereof on an outlet side.
- the flange is preferably arranged on the opening end on the inlet side or on the opening end on the outlet side.
- the side wall preferably includes three slit groups each of which includes a plurality of slits arranged to extend in the circumferential direction and arranged to extend through the side wall from an inner circumferential surface to the outer circumferential surface thereof. Two of the slit groups are defined in portions of the side wall which correspond to two adjacent corner portions in an upper half portion of the flange, while the remaining slit group is defined in a portion of the side wall which corresponds to a lower half portion of the flange.
- the upper and lower half portions are divided at a line parallel or substantially parallel to two opposing sides of the flange and passing through the central axis.
- a gap S 1 is preferably defined between a duct and an outside of each portion of the side wall which corresponds to a corner portion of the flange. Therefore, entry of a sufficient amount of air is accomplished through the two slit groups defined in the portions of the side wall which correspond to the corner portions.
- a gap S 2 is defined between the duct and an outside of a portion of the side wall which corresponds to a lower side of the flange. Therefore, entry of a sufficiently large amount of air is also accomplished through the slit group defined in the portion of the side wall which corresponds to the lower half portion of the flange. This makes it possible to make the most of an air intake effect of the slits.
- An axial fan according to a preferred embodiment of the present invention is also able to achieve a reduction in deterioration of an air volume characteristic in a surge range.
- FIG. 1 is a perspective view of an axial fan according to a first preferred embodiment of the present invention as viewed from an inlet side.
- FIG. 2 is a plan view of the axial fan illustrated in FIG. 1 as viewed from the inlet side.
- FIG. 3 is a perspective view of the axial fan illustrated in FIG. 1 , in which an impeller is not shown.
- FIG. 4 is a cross-sectional view illustrating a housing of the axial fan according to the first preferred embodiment of the present invention in a cross-section taken along a plane perpendicular to a central axis J 1 .
- FIG. 5 is a side view of the housing of the axial fan according to the first preferred embodiment of the present invention.
- FIG. 6 is a side view of the housing of the axial fan according to the first preferred embodiment of the present invention.
- FIG. 7 is a side view of the housing of the axial fan according to the first preferred embodiment of the present invention.
- FIG. 8 includes (A) a plan view of an electronic device according to a preferred embodiment of the present invention, and (B) a front view of the electronic device.
- FIG. 9 is a front view of the axial fan according to the first preferred embodiment of the present invention attached to a duct of the electronic device, as viewed from the inlet side.
- FIG. 10 is a cross-sectional view of a housing of an axial fan according to a second preferred embodiment of the present invention in a cross-section taken along a plane perpendicular to the central axis J 1 .
- FIG. 11 is a cross-sectional view of a housing of an axial fan according to a third preferred embodiment of the present invention in a cross-section taken along a plane perpendicular to the central axis J 1 .
- FIG. 12 is a cross-sectional view of a housing of an axial fan according to a fourth preferred embodiment of the present invention in a cross-section taken along a plane perpendicular to the central axis J 1 .
- a direction parallel or substantially parallel to a central axis J 1 will be referred to as an axial direction
- a radial direction centered on the central axis J 1 will be referred to as a radial direction.
- An axial fan A is preferably arranged to cool an electronic device 200 , such as, for example, a household electrical appliance, by discharging an air having a high temperature inside a casing 201 of the electronic device 200 to an outside thereof. Details thereof will be described in further detail below.
- the axial fan A includes a housing 10 , an impeller 20 , and a motor portion arranged to rotate the impeller.
- the impeller 20 preferably includes a substantially cylindrical impeller cup portion 22 and a plurality of blades 21 .
- the blades 21 are arranged to rotate about the central axis J 1 to produce an air flow.
- the blades 21 are preferably arranged on an outside surface of the impeller cup portion 22 such that the blades 21 are arranged at regular intervals in a circumferential direction about the central axis J 1 .
- the blades 21 are arranged to rotate in accordance with rotation of the impeller 20 .
- Rotation of the blades 21 causes an air to be pushed downward (i.e., in a downward direction in FIG. 1 ).
- the downward push of the air causes an air flow traveling in a direction parallel or substantially parallel to the central axis J 1 .
- an upper side and a lower side correspond to an inlet side and an outlet side, respectively.
- the motor portion preferably includes a rotor yoke, which is substantially in the shape of a covered cylinder.
- the impeller 20 is preferably arranged to be attached to an outside surface of the rotor yoke.
- One end portion of a shaft is joined and fixed to the rotor yoke.
- the rotor yoke is arranged to rotate with the shaft in a center thereof.
- a rotation axis of the shaft will be referred to as the central axis J 1 .
- the housing 10 preferably includes a side wall 11 , a base portion 12 , support ribs 13 , and a flange 14 .
- An inner circumferential surface of the side wall 11 is preferably curved and substantially cylindrical, while an external shape of the side wall 11 is preferably flat and substantially square.
- the side wall 11 preferably defines a hollow tube that includes openings at both axial ends. One opening end of the side wall 11 (i.e., on the upper side in each of FIGS. 1 and 3 ) is arranged on the inlet side, while the other opening end of the side wall (i.e., on the lower side in each of FIGS. 1 and 3 ) is arranged on the outlet side.
- a radially outer periphery of the impeller 20 is preferably arranged to be radially opposite from the inner circumferential surface of the side wall 11 . That is, the side wall 11 is arranged to define an air channel for the air flow which is produced when the impeller 20 is rotated about the central axis J 1 .
- a radial gap is arranged between the blades and the side wall 11 to prevent the blades 21 from coming into contact with the side wall 11 .
- the flange 14 is defined integrally with the opening end of the side wall 11 on the outlet side.
- the flange 14 is preferably substantially square shaped and arranged to project radially outward from an outer circumferential surface of the side wall 11 . Note that the flange 14 may be arranged on the opening end of the side wall 11 on the inlet side, instead of on the outlet side, in other preferred embodiments of the present invention.
- the outer circumferential surface of the side wall 11 includes side corresponding surfaces 11 f and corner corresponding surfaces 11 g.
- Each of the side corresponding surfaces 11 f is provided for a separate one of four sides of the flange 14 .
- Each of the corner corresponding surfaces 11 g is preferably provided for a separate one of four corner portions 14 a to 14 d (specifically, a first corner portion 14 a, a second corner portion 14 b, a third corner portion 14 c, and a fourth corner portion 14 d ) of the flange 14 .
- Each side corresponding surface 11 f is preferably defined by a flat surface
- each corner corresponding surface 11 g is preferably defined by an arc-shaped surface swelling outward.
- the side wall 11 has an upper opening portion at its upper end (on an inlet side), and a lower opening portion at its lower end (on an outlet side).
- the upper opening portion of the side wall 11 includes inclined surfaces 11 a and 11 d defined therein.
- the inclined surfaces 11 a and 11 d are arranged to gradually expand a cross section of the air channel which is perpendicular or substantially perpendicular to the central axis J 1 with decreasing distance from the upper end of the side wall 11 .
- the inclined surfaces 11 a and 11 d are arranged to be at increasingly greater distances from the central axis J 1 with increasing height in the direction parallel or substantially parallel to the central axis J 1 .
- the lower opening portion of the side wall 11 includes inclined surfaces 11 b and 11 e defined therein.
- the inclined surfaces 11 b and 11 e are arranged to gradually expand the cross section of the air channel which is perpendicular or substantially perpendicular to the central axis J 1 with decreasing distance from the lower end of the side wall 11 .
- the inclined surfaces 11 b and 11 e are arranged to be at increasingly greater distances from the central axis J 1 with decreasing height in the direction parallel to the central axis J 1 .
- the inclined surfaces 11 a and 11 b are defined in locations which correspond to the corner corresponding surfaces 11 g in the outer circumferential surface.
- the inclined surfaces 11 d and 11 e are defined in locations which correspond to the side corresponding surfaces 11 f in the outer circumferential surface.
- a portion of the side wall 11 at and near the opening end thereof on the outlet side is arranged in a tapered shape so that a cross-sectional area of the opening defined thereby increases with decreasing distance from the opening end on the outlet side.
- fitting holes are preferably defined in the four corner portions 14 a to 14 d of the flange 14 .
- the fitting holes are used to attach the axial fan A to a duct 206 provided inside the electronic device 200 , which will be further described below.
- Each of the fitting holes is preferably arranged to extend in the direction parallel or substantially parallel to the central axis J 1 through a corresponding one of the corner portions 14 a to 14 d.
- a straight surface 11 c is defined between the inclined surfaces 11 a and 11 b in the direction parallel or substantially parallel to the central axis J 1 .
- the radial distance between the central axis J 1 and the inner circumferential surface of the side wall 11 is substantially constant throughout an entire portion of the inner circumferential surface which corresponds to the straight surface 11 c.
- the side wall 11 is preferably defined through, for example, injection molding.
- the straight surface 11 c is inclined at a slight angle to the central axis J 1 to become more distant from the central axis J 1 with increasing height. This slight angle is referred to as a draft angle, and is set in order to facilitate mold release when a molded article is removed from molds. The draft angle scarcely affects the air volume characteristic of the axial fan A.
- the base portion 12 is arranged radially inward of the side wall 11 to support and fix the motor portion 30 .
- the base portion 12 is arranged at a level corresponding to that of a lower end portion of the side wall 11 .
- the base portion 12 is arranged substantially in the shape of a cylinder having a bottom and centered on the central axis J 1 .
- a bearing housing 12 a arranged substantially in the shape of a cylinder having a bottom and centered on the central axis J 1 is arranged in a center of the base portion 12 .
- the support ribs 13 which are preferably four in number, for example, are arranged on an outside surface of the base portion 12 to project radially outward therefrom.
- the four support ribs 13 for example, are preferably arranged in a circumferential direction of the outside surface of the base portion 12 , and centered on the central axis J 1 .
- Each of the support ribs 13 is joined and connected to the inner circumferential surface of the side wall 11 on a radial outside.
- the support ribs 13 are joined and connected to the inclined surfaces 11 b, which define portions of the inner circumferential surface of the side wall 11 . That is, the base portion 12 is supported by the side wall 11 through the four support ribs 13 .
- the side wall 11 , the base portion 12 , and the support ribs 13 are defined continuously and integrally with one another through injection molding.
- a material used in this injection molding preferably is a resin. Note, however, that application of the injection molding using the resin is not essential to the present invention. For example, a die-casting process using an aluminum alloy may be applied to define the side wall 11 , the base portion 12 , and the support ribs 13 continuously and integrally with each other.
- the impeller 20 the motor portion, and so on are not shown in FIG. 4 for the sake of convenience.
- the flange 14 is divided into an upper half portion and a lower half portion.
- the upper half portion is defined based on one side (i.e., an upper side) of the flange 14
- the lower half portion is defined based on an opposite side (i.e., a lower side) of the flange 14 with respect to the central axis J 1 .
- the housing 10 when the housing 10 is viewed from above the opening on the inlet side, the housing 10 can be divided into upper and lower halves at a line parallel or substantially parallel to two opposing sides of the housing 10 and passing through the central axis J 1 , and the upper and lower half portions of the flange 14 are defined on opposite sides of the line.
- the side wall 11 includes three slit groups 111 , 112 , and 113 (specifically, a first slit group 111 , a second slit group 112 , and a third slit group 113 ) defined therein.
- the slit groups 111 , 112 , and 113 include a plurality of slits 111 a, a plurality of slits 112 a, and a plurality of slits 113 a, respectively.
- the first and second slit groups 111 and 112 are defined in two of the corner corresponding surfaces 11 g on the outer circumferential surface of the side wall 11 .
- the first slit group 111 is defined in one of the corner corresponding surfaces 11 g which corresponds to the first corner portion 14 a of the flange 14
- the second slit group 112 is defined in one of the corner corresponding surfaces 11 g which corresponds to the second corner portion 14 b of the flange 14
- the first and second slit groups 111 and 112 are arranged in portions of the side wall 11 which correspond to the two adjacent corner portions 14 a and 14 b in the upper half portion of the flange 14
- the third slit group 113 is defined in a portion of the side wall 11 which corresponds to the lower half portion of the flange 14 .
- the third slit group 113 is arranged to extend over one of the side corresponding surfaces 11 f which corresponds to the lower side of the flange 14 and two of the corner corresponding surfaces 11 g which correspond to the third and fourth corner portions 14 c and 14 d of the flange 14 , which are adjacent to the side corresponding surface 11 f.
- the slits 111 a, 112 a, or 113 a in each of the slit groups 111 , 112 , and 113 are arranged in a circumferential direction of the side wall 11 , and are arranged to extend through the side wall 11 from the straight surface 11 c (i.e., the inner circumferential surface) to the corner corresponding surface 11 g or the side corresponding surface 11 f (i.e., the outer circumferential surface) of the side wall 11 .
- the slits 111 a in the first slit group 111 are arranged to extend in the same direction (i.e., have the same through direction T).
- the slits 112 a in the second slit group 112 are arranged to extend in the same direction (i.e., have the same through direction T).
- the slits 113 a in the third slit group 113 are arranged to extend in the same direction (i.e., have the same through direction T).
- the slits 111 a, 112 a, or 113 a in each of the three slit groups 111 , 112 , and 113 have a different through direction T from that of the slits in any other of the three slit groups 111 , 112 , and 113 .
- each of the slits 111 a, 112 a, and 113 a in the slit groups 111 , 112 , and 113 , respectively, when viewed from a radial outside, is inclined at a specified angle to the direction parallel or substantially parallel to the central axis J 1 .
- each of the slits 111 a which are arranged at circumferential ends of the first slit group 111 is arranged to extend over a corresponding one of the corner corresponding surfaces 11 g and an adjacent one of the side corresponding surfaces 11 f
- each of the slits 112 a which are arranged at circumferential ends of the second slit group 112 is arranged to extend over a corresponding one of the corner corresponding surfaces 11 g and an adjacent one of the side corresponding surfaces 11 f.
- one end of the slit 111 a or 112 a in the longitudinal direction is positioned in the corner corresponding surface 11 g, while the other end of the slit 111 a or 112 a in the longitudinal direction is positioned in the side corresponding surface 11 f.
- a portion of the side wall 11 which corresponds to the straight surface 11 c is preferably circular, and the outer circumferential surface of the side wall is made up of the side corresponding surfaces 11 f, each of which is preferably defined by a flat surface, and the corner corresponding surfaces 11 g, each of which is defined by a substantially arc-shaped surface. Accordingly, a portion of the side wall 11 which corresponds to each side corresponding surface 11 f has a thickness smaller than that of a portion of the side wall 11 which corresponds to each corner corresponding surface 11 g.
- the electronic device 200 is installed, for example, in a household electrical appliance or the like.
- the electronic device 200 preferably includes the casing 201 , and also includes heating elements 204 , the duct 206 , and the above-described axial fan A arranged inside the casing 201 .
- An interior of the casing 201 is divided into an element space 202 in which the heating elements 204 are arranged, and a fan space 203 in which the duct 206 and the axial fan A are arranged.
- the axial fan A is attached to an inside of the duct 206 , and the duct 206 is thus arranged to discharge an air having a high temperature inside the element space 202 to an outside of the casing 201 .
- an air entrance portion 207 of the duct 206 is arranged to open into the element space 202 , and an air exit portion 208 of the duct 206 is connected to an air outlet 205 defined in the casing 201 .
- a heat sink 209 is arranged in the air entrance portion 207 of the duct 206 .
- the axial fan A is arranged in the air exit portion 208 of the duct 206 .
- a cross-section (which defines a cross-section of an air channel) of the air exit portion 208 is preferably substantially square or substantially rectangular.
- the axial fan A is installed in the air exit portion 208 so as to cross the air channel.
- the width of the cross-section of the air exit portion 208 is approximately equal to the width of the flange 14 of the axial fan A.
- the height of the cross-section of the air exit portion 208 is slightly greater than the height of the flange 14 of the axial fan A, i.e., the distance between the side corresponding surface 11 f corresponding to the upper side of the flange 14 and the side corresponding surface 11 f corresponding to the lower side of the flange 14 .
- a minute gap is defined between the duct 206 and each of the upper, right-hand, and left-hand side corresponding surfaces 11 f of the side wall 11 of the axial fan A.
- a gap S 1 is defined between the duct 206 and each of the four corner corresponding surfaces 11 g of the side wall 11
- a gap S 2 is defined between the duct 206 and the lower side corresponding surface 11 f. That is, the axial fan A is installed in the air exit portion 208 of the duct 206 such that the first and second slit groups 111 and 112 are arranged on an upper side, that each of the upper side and lateral sides of the flange 14 and a channel wall together define the minute gap therebetween, and that the lower side of the flange 14 and the channel wall together define the gap S 2 therebetween.
- the minute gaps mentioned above are clearance spaces needed for the attachment of the axial fan A to the duct 206 , and that the gap S 2 is significantly greater than these minute gaps.
- the gaps S 1 are defined outside the corner corresponding surfaces 11 g of the side wall 11 , those of the slits 111 a, 112 a, and 113 a in the slit groups 111 , 112 , and 113 which are defined in the corner corresponding surfaces 11 g permit entry of an sufficient amount of air therethrough.
- the gap S 2 is defined outside those of the slits 113 a in the third slit group 113 which are defined in the lower side corresponding surface 11 f, a sufficient amount of air is permitted to enter through these slits 113 a.
- the entry of a sufficient amount of air through the slits 113 a in the third slit group 113 is ensured by both of the gaps S 1 and the gap S 2 .
- the entry of a sufficient amount of air is accomplished through the slits 111 a, 112 a, and 113 a because the slits 111 a, 112 a, and 113 a are mostly defined in those portions of the side wall 11 which have the gaps S 1 outside such that portions of the duct 206 cannot completely cover the slits 111 a, 112 a, and 113 a to thereby present the flow of air there into.
- the slits 113 a in the third slit group 113 may be defined only in the side corresponding surface 11 f corresponding to the lower side of the flange 14 . Also note that, in a modification of the present preferred embodiment, the slits 113 a in the third slit group 113 may be defined only in one of the adjacent corner corresponding surfaces 11 g.
- the slits 111 a or 112 a which are arranged at both circumferential ends thereof are arranged to extend over the corresponding one of the corner corresponding surfaces 11 g and the adjacent one of the side corresponding surfaces 11 f.
- an outside of a portion thereof which is positioned in the side corresponding surface 11 f is covered by the duct 206 , and therefore, air does not enter through this portion.
- the gap S 1 exists outside a portion thereof which is positioned in the corner corresponding surface 11 g, air is allowed to enter through this portion and exit through the entire opening on the outlet side, making it possible for a sufficient amount of air to enter into the axial fan A. Therefore, there is no need to prevent a portion of any of the slits 111 a and 112 a from extending over any side corresponding surface 11 f, and this makes it possible to increase the number of slits 111 a or 112 a.
- each slit group made up of a plurality of slits arranged in the circumferential direction and having the same through direction T
- the dimensions along the through direction T of slits that are closer to either circumferential end of the slit group are greater than those of slits that are closer to the middle of the slit group.
- the dimension of each slit along the through direction T corresponds to the length of an air channel through the slit.
- the slits that are relatively close to either circumferential end of the slit group involve a relatively large air channel resistance.
- the outer circumferential surface of the side wall 11 is made up of the side corresponding surfaces 11 f, each of which is preferably defined by a flat surface, and the corner corresponding surfaces 11 g, each of which is preferably defined by an arc-shaped surface, and portions of the side wall 11 which correspond to the side corresponding surfaces 11 f are arranged to have a smaller thickness than that of portions of the side wall 11 which correspond to the corner corresponding surfaces 11 g.
- the slits 111 a, 112 a, or 113 a which are arranged to extend over the corresponding one of the corner corresponding surfaces 11 g and the adjacent one of the side corresponding surfaces 11 f (especially, those which are arranged at both circumferential ends of the slit group) have a reduced thickness along the through direction T, that is, a shorter air channel therethrough, and hence a reduced air channel resistance.
- a cross-sectional area (i.e., a cross-sectional area of the air channel) of the inner circumferential surface of the side wall 11 which is perpendicular or substantially perpendicular to the central axis J 1 is smaller at levels at which the straight surface 11 c is defined than at levels at which the inclined surfaces 11 a and 11 d are defined.
- a flow of air passing through the straight surface 11 c has a greater flow velocity than that of a flow of air passing through the inclined surfaces 11 a and 11 d. Because the flow of air passing through the straight surface 11 c has a greater flow velocity than that of a flow of air in any other region, a negative pressure is generated relative to an atmospheric pressure in a region around the side wall 11 . This makes it easier for air to flow into the space inside the inner circumferential surface of the side wall 11 through the slits 111 a, 112 a, and 113 a in the slit groups 111 , 112 , and 113 , respectively.
- the air then passes through the straight surface 11 c and the inclined surfaces 11 b and 11 e to be discharged out of the axial fan A.
- the cross-sectional area i.e., the cross-sectional area of the air channel
- the cross-sectional area of the inner circumferential surface of the side wall 11 which is perpendicular or substantially perpendicular to the central axis J 1 is greater at levels at which the inclined surfaces 11 b and 11 e are defined than at the levels at which the straight surface 11 c is defined. This contributes to an increase in the volume or air being discharged.
- An axial fan A according to the present preferred embodiment is similar to the axial fan A according to the first preferred embodiment described above except in the structures of the first and second slit groups 111 and 112 .
- all of the slits 111 a and 112 a in the first and second slit groups 111 and 112 , respectively, have the same through direction T. Therefore, it is possible to arrange a mold that is used to define the slits 111 a and a mold that is used to define the slits 112 a through, for example, injection molding to be slid in the same direction at the time of mold release.
- a mold release operation of the present preferred embodiment is thereby made easier than a mold release operation of the previously described preferred embodiment.
- Other structural features, actions, and effects of the present preferred embodiment are similar to those of the first preferred embodiment described above.
- An axial fan A according to the present preferred embodiment is similar to the axial fan A according to the first preferred embodiment described above except that the number of slit groups is preferably changed from three to four.
- the side wall 11 includes four slit groups 121 , 122 , 123 , and 124 (specifically, a first slit group 121 , a second slit group 122 , a third slit group 123 , and a fourth slit group 124 ) defined therein.
- the slit groups 121 , 122 , 123 , and 124 preferably include a plurality of slits 121 a, a plurality of slits 122 a, a plurality of slits 123 a, and a plurality of slits 124 a, respectively.
- Each of the four slit groups 121 , 122 , 123 , and 124 is defined in a separate one of the four corner corresponding surfaces 11 g on the outer circumferential surface of the side wall 11 . More specifically, as in the first preferred embodiment described above, the first and second slit groups 121 and 122 are defined in the corner corresponding surfaces 11 g corresponding to the first and second corner portions 14 a and 14 b, respectively, of the flange 14 .
- the third slit group 123 is defined in the corner corresponding surface 11 g corresponding to the third corner portion 14 c of the flange 14 .
- the fourth slit group 124 is defined in the corner corresponding surface 11 g corresponding to the fourth corner portion 14 d of the flange 14 .
- first and second slit groups 121 and 122 are arranged in portions of the side wall 11 which correspond to the two adjacent corner portions 14 a and 14 b in the upper half portion of the flange 14 .
- the third and fourth slit groups 123 and 124 are arranged in portions of the side wall 11 which correspond to the two adjacent corner portions 14 c and 14 d in the lower half portion of the flange 14 .
- the entry of a sufficient amount of air is accomplished through each of the slit groups 121 , 122 , 123 , and 124 because the gap S 1 is defined outside each of the four corner corresponding surfaces 11 g of the side wall 11 .
- the entry of a sufficient amount of air through each of the third and fourth slit groups 123 and 124 is accomplished even if the axial fan A is attached not to the duct 206 according to the first preferred embodiment described above but to a duct which is so shaped that the lower side corresponding surface 11 f of the side wall 11 is arranged substantially in contact with the duct without the gap S 2 defined between the duct and the flange 14 .
- Other structural features, actions, and effects of the present preferred embodiment are similar to those of the first preferred embodiment described above.
- An axial fan A according to the present preferred embodiment is similar to the axial fan A according to the first preferred embodiment described above except that the third slit group 113 is eliminated, leaving only the first and second slit groups 111 and 112 . Even in this case, the entry of a sufficient amount of air is accomplished through each of the slit groups 111 and 112 , and a sufficient air intake effect of the slits 111 a and 112 a is achieved.
- Other structural features, actions, and effects of the present preferred embodiment are similar to those of the first preferred embodiment described above.
Abstract
Description
- 1. Field of the Invention
- The present invention relates to an axial fan and an electronic device including the same.
- 2. Description of the Related Art
- Axial fans whose housings include slits have been known. For example, World Intellectual Property Organization Publication No. 2009/057063 discloses one such conventional axial fan. This conventional axial fan includes an impeller in which a plurality of blades are arranged in a circumferential direction about a central axis, and a housing (i.e., a wind tunnel portion) arranged radially outward of the impeller to surround the impeller. The housing includes a plurality of slits that are arranged in the circumferential direction and arranged to extend through the housing from an inner circumferential surface to an outer circumferential surface thereof.
- The conventional axial fan as described above is often used as a cooling fan for an electronic device or the like, and is often attached to an exhaust duct provided in a casing of an electronic device or the like to define an air channel in the casing. In this case, the axial fan is sometimes attached to the duct such that an outer circumference of the axial fan is covered by a surface of the duct depending on the shape of the duct. In this case, the slits will be covered by the presence of the surface of the duct on the outside of the axial fan. When this happens, inflow of air into the housing through the slits is blocked, which thus makes it impossible to increase an air volume in a surge range, that is, resulting in a failure to make the most of an air intake effect of the slits.
- An axial fan according to a preferred embodiment of the present invention includes an impeller arranged to rotate about a central axis, and including a plurality of blades centered on the central axis, arranged to project radially outward, and arranged in a circumferential direction; and a housing including a side wall arranged to have openings at both axial ends thereof and arranged to surround an outer circumference of the impeller, and a substantially square or substantially rectangular flange arranged to project radially outward from an outer circumferential surface of the side wall. The side wall preferably includes an opening end at the axial end thereof on an inlet side and another opening end at the axial end thereof on an outlet side. The flange is preferably arranged on the opening end on the inlet side or on the opening end on the outlet side. The side wall preferably includes three slit groups each of which includes a plurality of slits arranged to extend in the circumferential direction and arranged to extend through the side wall from an inner circumferential surface to the outer circumferential surface thereof. Two of the slit groups are defined in portions of the side wall which correspond to two adjacent corner portions in an upper half portion of the flange, while the remaining slit group is defined in a portion of the side wall which corresponds to a lower half portion of the flange. The upper and lower half portions are divided at a line parallel or substantially parallel to two opposing sides of the flange and passing through the central axis.
- According to the above-described preferred embodiment, a gap S1 is preferably defined between a duct and an outside of each portion of the side wall which corresponds to a corner portion of the flange. Therefore, entry of a sufficient amount of air is accomplished through the two slit groups defined in the portions of the side wall which correspond to the corner portions. In addition, a gap S2 is defined between the duct and an outside of a portion of the side wall which corresponds to a lower side of the flange. Therefore, entry of a sufficiently large amount of air is also accomplished through the slit group defined in the portion of the side wall which corresponds to the lower half portion of the flange. This makes it possible to make the most of an air intake effect of the slits.
- An axial fan according to a preferred embodiment of the present invention is also able to achieve a reduction in deterioration of an air volume characteristic in a surge range.
- The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.
-
FIG. 1 is a perspective view of an axial fan according to a first preferred embodiment of the present invention as viewed from an inlet side. -
FIG. 2 is a plan view of the axial fan illustrated inFIG. 1 as viewed from the inlet side. -
FIG. 3 is a perspective view of the axial fan illustrated inFIG. 1 , in which an impeller is not shown. -
FIG. 4 is a cross-sectional view illustrating a housing of the axial fan according to the first preferred embodiment of the present invention in a cross-section taken along a plane perpendicular to a central axis J1. -
FIG. 5 is a side view of the housing of the axial fan according to the first preferred embodiment of the present invention. -
FIG. 6 is a side view of the housing of the axial fan according to the first preferred embodiment of the present invention. -
FIG. 7 is a side view of the housing of the axial fan according to the first preferred embodiment of the present invention. -
FIG. 8 includes (A) a plan view of an electronic device according to a preferred embodiment of the present invention, and (B) a front view of the electronic device. -
FIG. 9 is a front view of the axial fan according to the first preferred embodiment of the present invention attached to a duct of the electronic device, as viewed from the inlet side. -
FIG. 10 is a cross-sectional view of a housing of an axial fan according to a second preferred embodiment of the present invention in a cross-section taken along a plane perpendicular to the central axis J1. -
FIG. 11 is a cross-sectional view of a housing of an axial fan according to a third preferred embodiment of the present invention in a cross-section taken along a plane perpendicular to the central axis J1. -
FIG. 12 is a cross-sectional view of a housing of an axial fan according to a fourth preferred embodiment of the present invention in a cross-section taken along a plane perpendicular to the central axis J1. - Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the preferred embodiments described below. Also note that variations and modifications can be made appropriately as long as desired effects of the present invention are not impaired. Also note that the preferred embodiments described below may be combined with other preferred embodiments of the present invention. For the sake of convenience, it is assumed in the following description of the preferred embodiments of the present invention that a vertical direction of each figure is referred to as a “vertical direction”. Note, however, that this assumption should not be construed to restrict an orientation of any device or member in actual use. Also note that, for the sake of convenience in description, a direction parallel or substantially parallel to a central axis J1 will be referred to as an axial direction, and a radial direction centered on the central axis J1 will be referred to as a radial direction.
- A first preferred embodiment of the present invention will now be described below with reference to
FIGS. 1-9 . An axial fan A according to the present preferred embodiment is preferably arranged to cool anelectronic device 200, such as, for example, a household electrical appliance, by discharging an air having a high temperature inside acasing 201 of theelectronic device 200 to an outside thereof. Details thereof will be described in further detail below. - An overall structure of the axial fan A will now be described below. Referring to
FIGS. 1 and 2 , the axial fan A includes ahousing 10, animpeller 20, and a motor portion arranged to rotate the impeller. - The
impeller 20 preferably includes a substantially cylindricalimpeller cup portion 22 and a plurality ofblades 21. Theblades 21 are arranged to rotate about the central axis J1 to produce an air flow. Referring toFIG. 2 , theblades 21 are preferably arranged on an outside surface of theimpeller cup portion 22 such that theblades 21 are arranged at regular intervals in a circumferential direction about the central axis J1. Theblades 21 are arranged to rotate in accordance with rotation of theimpeller 20. Rotation of theblades 21 causes an air to be pushed downward (i.e., in a downward direction inFIG. 1 ). The downward push of the air causes an air flow traveling in a direction parallel or substantially parallel to the central axis J1. Note that, inFIGS. 1 and 3 , an upper side and a lower side correspond to an inlet side and an outlet side, respectively. - The motor portion preferably includes a rotor yoke, which is substantially in the shape of a covered cylinder. The
impeller 20 is preferably arranged to be attached to an outside surface of the rotor yoke. One end portion of a shaft is joined and fixed to the rotor yoke. The rotor yoke is arranged to rotate with the shaft in a center thereof. A rotation axis of the shaft will be referred to as the central axis J1. - The
housing 10 preferably includes aside wall 11, abase portion 12,support ribs 13, and aflange 14. An inner circumferential surface of theside wall 11 is preferably curved and substantially cylindrical, while an external shape of theside wall 11 is preferably flat and substantially square. Theside wall 11 preferably defines a hollow tube that includes openings at both axial ends. One opening end of the side wall 11 (i.e., on the upper side in each ofFIGS. 1 and 3 ) is arranged on the inlet side, while the other opening end of the side wall (i.e., on the lower side in each ofFIGS. 1 and 3 ) is arranged on the outlet side. A radially outer periphery of theimpeller 20 is preferably arranged to be radially opposite from the inner circumferential surface of theside wall 11. That is, theside wall 11 is arranged to define an air channel for the air flow which is produced when theimpeller 20 is rotated about the central axis J1. A radial gap is arranged between the blades and theside wall 11 to prevent theblades 21 from coming into contact with theside wall 11. - The
flange 14 is defined integrally with the opening end of theside wall 11 on the outlet side. Theflange 14 is preferably substantially square shaped and arranged to project radially outward from an outer circumferential surface of theside wall 11. Note that theflange 14 may be arranged on the opening end of theside wall 11 on the inlet side, instead of on the outlet side, in other preferred embodiments of the present invention. - The outer circumferential surface of the
side wall 11 includesside corresponding surfaces 11 f andcorner corresponding surfaces 11 g. Each of theside corresponding surfaces 11 f is provided for a separate one of four sides of theflange 14. Each of thecorner corresponding surfaces 11 g is preferably provided for a separate one of fourcorner portions 14 a to 14 d (specifically, afirst corner portion 14 a, asecond corner portion 14 b, athird corner portion 14 c, and afourth corner portion 14 d) of theflange 14. Eachside corresponding surface 11 f is preferably defined by a flat surface, while eachcorner corresponding surface 11 g is preferably defined by an arc-shaped surface swelling outward. - The
side wall 11 has an upper opening portion at its upper end (on an inlet side), and a lower opening portion at its lower end (on an outlet side). The upper opening portion of theside wall 11 includesinclined surfaces side wall 11. In other words, theinclined surfaces side wall 11 includesinclined surfaces side wall 11. In other words, theinclined surfaces - The inclined surfaces 11 a and 11 b are defined in locations which correspond to the
corner corresponding surfaces 11 g in the outer circumferential surface. The inclined surfaces 11 d and 11 e are defined in locations which correspond to theside corresponding surfaces 11 f in the outer circumferential surface. As a result of theinclined surfaces side wall 11 at and near the opening end thereof on the inlet side is arranged in a tapered shape so that a cross-sectional area of the opening defined thereby increases with decreasing distance from the opening end on the inlet side. Meanwhile, as a result of theinclined surfaces side wall 11 at and near the opening end thereof on the outlet side is arranged in a tapered shape so that a cross-sectional area of the opening defined thereby increases with decreasing distance from the opening end on the outlet side. - Although not shown in the figures, fitting holes are preferably defined in the four
corner portions 14 a to 14 d of theflange 14. The fitting holes are used to attach the axial fan A to aduct 206 provided inside theelectronic device 200, which will be further described below. Each of the fitting holes is preferably arranged to extend in the direction parallel or substantially parallel to the central axis J1 through a corresponding one of thecorner portions 14 a to 14 d. - A
straight surface 11 c is defined between theinclined surfaces side wall 11 is substantially constant throughout an entire portion of the inner circumferential surface which corresponds to thestraight surface 11 c. Theside wall 11 is preferably defined through, for example, injection molding. Thestraight surface 11 c is inclined at a slight angle to the central axis J1 to become more distant from the central axis J1 with increasing height. This slight angle is referred to as a draft angle, and is set in order to facilitate mold release when a molded article is removed from molds. The draft angle scarcely affects the air volume characteristic of the axial fan A. - The
base portion 12 is arranged radially inward of theside wall 11 to support and fix the motor portion 30. In more detail, thebase portion 12 is arranged at a level corresponding to that of a lower end portion of theside wall 11. Thebase portion 12 is arranged substantially in the shape of a cylinder having a bottom and centered on the central axis J1. A bearing housing 12 a arranged substantially in the shape of a cylinder having a bottom and centered on the central axis J1 is arranged in a center of thebase portion 12. - The
support ribs 13, which are preferably four in number, for example, are arranged on an outside surface of thebase portion 12 to project radially outward therefrom. In addition, the foursupport ribs 13, for example, are preferably arranged in a circumferential direction of the outside surface of thebase portion 12, and centered on the central axis J1. Each of thesupport ribs 13 is joined and connected to the inner circumferential surface of theside wall 11 on a radial outside. In more detail, thesupport ribs 13 are joined and connected to theinclined surfaces 11 b, which define portions of the inner circumferential surface of theside wall 11. That is, thebase portion 12 is supported by theside wall 11 through the foursupport ribs 13. Theside wall 11, thebase portion 12, and thesupport ribs 13 are defined continuously and integrally with one another through injection molding. A material used in this injection molding preferably is a resin. Note, however, that application of the injection molding using the resin is not essential to the present invention. For example, a die-casting process using an aluminum alloy may be applied to define theside wall 11, thebase portion 12, and thesupport ribs 13 continuously and integrally with each other. - Next, slits 111 a, 112 a, and 113 a defined in the
side wall 11 of thehousing 10 will now be described in detail below with reference toFIGS. 4 to 7 . Note that theimpeller 20, the motor portion, and so on are not shown inFIG. 4 for the sake of convenience. Referring toFIG. 4 , it is assumed herein that theflange 14 is divided into an upper half portion and a lower half portion. The upper half portion is defined based on one side (i.e., an upper side) of theflange 14, while the lower half portion is defined based on an opposite side (i.e., a lower side) of theflange 14 with respect to the central axis J1. In other words, when thehousing 10 is viewed from above the opening on the inlet side, thehousing 10 can be divided into upper and lower halves at a line parallel or substantially parallel to two opposing sides of thehousing 10 and passing through the central axis J1, and the upper and lower half portions of theflange 14 are defined on opposite sides of the line. - The
side wall 11 includes three slitgroups first slit group 111, asecond slit group 112, and a third slit group 113) defined therein. The slit groups 111, 112, and 113 include a plurality ofslits 111 a, a plurality ofslits 112 a, and a plurality ofslits 113 a, respectively. The first andsecond slit groups corner corresponding surfaces 11 g on the outer circumferential surface of theside wall 11. More specifically, thefirst slit group 111 is defined in one of thecorner corresponding surfaces 11 g which corresponds to thefirst corner portion 14 a of theflange 14, while thesecond slit group 112 is defined in one of thecorner corresponding surfaces 11 g which corresponds to thesecond corner portion 14 b of theflange 14. That is, the first andsecond slit groups side wall 11 which correspond to the twoadjacent corner portions flange 14. Thethird slit group 113 is defined in a portion of theside wall 11 which corresponds to the lower half portion of theflange 14. More specifically, thethird slit group 113 is arranged to extend over one of theside corresponding surfaces 11 f which corresponds to the lower side of theflange 14 and two of thecorner corresponding surfaces 11 g which correspond to the third andfourth corner portions flange 14, which are adjacent to theside corresponding surface 11 f. - The
slits slit groups side wall 11, and are arranged to extend through theside wall 11 from thestraight surface 11 c (i.e., the inner circumferential surface) to thecorner corresponding surface 11 g or theside corresponding surface 11 f (i.e., the outer circumferential surface) of theside wall 11. Theslits 111 a in thefirst slit group 111 are arranged to extend in the same direction (i.e., have the same through direction T). Theslits 112 a in thesecond slit group 112 are arranged to extend in the same direction (i.e., have the same through direction T). Theslits 113 a in thethird slit group 113 are arranged to extend in the same direction (i.e., have the same through direction T). Theslits slit groups slit groups slits slit groups - Referring to
FIGS. 5 and 6 , each of theslits 111 a which are arranged at circumferential ends of thefirst slit group 111 is arranged to extend over a corresponding one of thecorner corresponding surfaces 11 g and an adjacent one of theside corresponding surfaces 11 f, and similarly, each of theslits 112 a which are arranged at circumferential ends of thesecond slit group 112 is arranged to extend over a corresponding one of thecorner corresponding surfaces 11 g and an adjacent one of theside corresponding surfaces 11 f. More specifically, when viewed from the radial outside, one end of theslit corner corresponding surface 11 g, while the other end of theslit side corresponding surface 11 f. - As described above, a portion of the
side wall 11 which corresponds to thestraight surface 11 c is preferably circular, and the outer circumferential surface of the side wall is made up of theside corresponding surfaces 11 f, each of which is preferably defined by a flat surface, and thecorner corresponding surfaces 11 g, each of which is defined by a substantially arc-shaped surface. Accordingly, a portion of theside wall 11 which corresponds to eachside corresponding surface 11 f has a thickness smaller than that of a portion of theside wall 11 which corresponds to eachcorner corresponding surface 11 g. - Next, the
electronic device 200 according to the present preferred embodiment will now be described below with reference toFIGS. 8 and 9 . Theelectronic device 200 is installed, for example, in a household electrical appliance or the like. - The
electronic device 200 preferably includes thecasing 201, and also includesheating elements 204, theduct 206, and the above-described axial fan A arranged inside thecasing 201. An interior of thecasing 201 is divided into anelement space 202 in which theheating elements 204 are arranged, and afan space 203 in which theduct 206 and the axial fan A are arranged. The axial fan A is attached to an inside of theduct 206, and theduct 206 is thus arranged to discharge an air having a high temperature inside theelement space 202 to an outside of thecasing 201. In thefan space 203, anair entrance portion 207 of theduct 206 is arranged to open into theelement space 202, and anair exit portion 208 of theduct 206 is connected to anair outlet 205 defined in thecasing 201. In addition, aheat sink 209 is arranged in theair entrance portion 207 of theduct 206. - The axial fan A is arranged in the
air exit portion 208 of theduct 206. A cross-section (which defines a cross-section of an air channel) of theair exit portion 208 is preferably substantially square or substantially rectangular. The axial fan A is installed in theair exit portion 208 so as to cross the air channel. The width of the cross-section of theair exit portion 208 is approximately equal to the width of theflange 14 of the axial fan A. The height of the cross-section of theair exit portion 208 is slightly greater than the height of theflange 14 of the axial fan A, i.e., the distance between theside corresponding surface 11 f corresponding to the upper side of theflange 14 and theside corresponding surface 11 f corresponding to the lower side of theflange 14. As a result, referring toFIG. 9 , a minute gap is defined between theduct 206 and each of the upper, right-hand, and left-handside corresponding surfaces 11 f of theside wall 11 of the axial fan A. In addition, a gap S1 is defined between theduct 206 and each of the fourcorner corresponding surfaces 11 g of theside wall 11, while a gap S2 is defined between theduct 206 and the lowerside corresponding surface 11 f. That is, the axial fan A is installed in theair exit portion 208 of theduct 206 such that the first andsecond slit groups flange 14 and a channel wall together define the minute gap therebetween, and that the lower side of theflange 14 and the channel wall together define the gap S2 therebetween. Note that the minute gaps mentioned above are clearance spaces needed for the attachment of the axial fan A to theduct 206, and that the gap S2 is significantly greater than these minute gaps. - According to the present preferred embodiment, because the gaps S1 are defined outside the
corner corresponding surfaces 11 g of theside wall 11, those of theslits slit groups corner corresponding surfaces 11 g permit entry of an sufficient amount of air therethrough. Moreover, because the gap S2 is defined outside those of theslits 113 a in thethird slit group 113 which are defined in the lowerside corresponding surface 11 f, a sufficient amount of air is permitted to enter through theseslits 113 a. That is, the entry of a sufficient amount of air through theslits 113 a in thethird slit group 113 is ensured by both of the gaps S1 and the gap S2. As described above, even when the axial fan A is attached to therectangular duct 206, the entry of a sufficient amount of air is accomplished through theslits slits side wall 11 which have the gaps S1 outside such that portions of theduct 206 cannot completely cover theslits slits slits 113 a in thethird slit group 113 may be defined only in theside corresponding surface 11 f corresponding to the lower side of theflange 14. Also note that, in a modification of the present preferred embodiment, theslits 113 a in thethird slit group 113 may be defined only in one of the adjacentcorner corresponding surfaces 11 g. - In each of the first and
second slit groups slits corner corresponding surfaces 11 g and the adjacent one of theside corresponding surfaces 11 f. Regarding each of theseslits side corresponding surface 11 f is covered by theduct 206, and therefore, air does not enter through this portion. However, because the gap S1 exists outside a portion thereof which is positioned in thecorner corresponding surface 11 g, air is allowed to enter through this portion and exit through the entire opening on the outlet side, making it possible for a sufficient amount of air to enter into the axial fan A. Therefore, there is no need to prevent a portion of any of theslits side corresponding surface 11 f, and this makes it possible to increase the number ofslits - In contrast to the present preferred embodiment, in the case where the outer circumferential surface of the
side wall 11 is arranged to be entirely cylindrical so that a cross-section of theside wall 11 taken along a plane perpendicular to the central axis J1 has a uniform thickness throughout, for example, regarding each slit group made up of a plurality of slits arranged in the circumferential direction and having the same through direction T, the dimensions along the through direction T of slits that are closer to either circumferential end of the slit group are greater than those of slits that are closer to the middle of the slit group. The dimension of each slit along the through direction T corresponds to the length of an air channel through the slit. Thus, the slits that are relatively close to either circumferential end of the slit group involve a relatively large air channel resistance. In the axial fan A according to the present preferred embodiment, however, the outer circumferential surface of theside wall 11 is made up of theside corresponding surfaces 11 f, each of which is preferably defined by a flat surface, and thecorner corresponding surfaces 11 g, each of which is preferably defined by an arc-shaped surface, and portions of theside wall 11 which correspond to theside corresponding surfaces 11 f are arranged to have a smaller thickness than that of portions of theside wall 11 which correspond to thecorner corresponding surfaces 11 g. Therefore, within each of theslit groups slits corner corresponding surfaces 11 g and the adjacent one of theside corresponding surfaces 11 f (especially, those which are arranged at both circumferential ends of the slit group) have a reduced thickness along the through direction T, that is, a shorter air channel therethrough, and hence a reduced air channel resistance. - Furthermore, air that stays on the inlet side of the axial fan A flows into a space inside the
side wall 11 through the inner circumferential surface of theside wall 11, more specifically, theinclined surfaces side wall 11 which is perpendicular or substantially perpendicular to the central axis J1 is smaller at levels at which thestraight surface 11 c is defined than at levels at which theinclined surfaces straight surface 11 c has a greater flow velocity than that of a flow of air passing through theinclined surfaces straight surface 11 c has a greater flow velocity than that of a flow of air in any other region, a negative pressure is generated relative to an atmospheric pressure in a region around theside wall 11. This makes it easier for air to flow into the space inside the inner circumferential surface of theside wall 11 through theslits slit groups straight surface 11 c and theinclined surfaces side wall 11 which is perpendicular or substantially perpendicular to the central axis J1 is greater at levels at which theinclined surfaces straight surface 11 c is defined. This contributes to an increase in the volume or air being discharged. - A second preferred embodiment of the present invention will now be described below with reference to
FIG. 10 . An axial fan A according to the present preferred embodiment is similar to the axial fan A according to the first preferred embodiment described above except in the structures of the first andsecond slit groups - In the present preferred embodiment, all of the
slits second slit groups slits 111 a and a mold that is used to define theslits 112 a through, for example, injection molding to be slid in the same direction at the time of mold release. A mold release operation of the present preferred embodiment is thereby made easier than a mold release operation of the previously described preferred embodiment. Other structural features, actions, and effects of the present preferred embodiment are similar to those of the first preferred embodiment described above. - A third preferred embodiment of the present invention will now be described below with reference to
FIG. 11 . An axial fan A according to the present preferred embodiment is similar to the axial fan A according to the first preferred embodiment described above except that the number of slit groups is preferably changed from three to four. - The
side wall 11 according to the present preferred embodiment includes four slitgroups first slit group 121, asecond slit group 122, athird slit group 123, and a fourth slit group 124) defined therein. The slit groups 121, 122, 123, and 124 preferably include a plurality ofslits 121 a, a plurality ofslits 122 a, a plurality ofslits 123 a, and a plurality ofslits 124 a, respectively. Each of the fourslit groups corner corresponding surfaces 11 g on the outer circumferential surface of theside wall 11. More specifically, as in the first preferred embodiment described above, the first andsecond slit groups corner corresponding surfaces 11 g corresponding to the first andsecond corner portions flange 14. Thethird slit group 123 is defined in thecorner corresponding surface 11 g corresponding to thethird corner portion 14 c of theflange 14. Thefourth slit group 124 is defined in thecorner corresponding surface 11 g corresponding to thefourth corner portion 14 d of theflange 14. That is, the first andsecond slit groups side wall 11 which correspond to the twoadjacent corner portions flange 14. The third andfourth slit groups side wall 11 which correspond to the twoadjacent corner portions flange 14. - Also in the present preferred embodiment, even when the axial fan A is attached to the
rectangular duct 206, the entry of a sufficient amount of air is accomplished through each of theslit groups corner corresponding surfaces 11 g of theside wall 11. This results in a sufficient air intake effect of theslits fourth slit groups duct 206 according to the first preferred embodiment described above but to a duct which is so shaped that the lowerside corresponding surface 11 f of theside wall 11 is arranged substantially in contact with the duct without the gap S2 defined between the duct and theflange 14. Other structural features, actions, and effects of the present preferred embodiment are similar to those of the first preferred embodiment described above. - A fourth preferred embodiment of the present invention will now be described below with reference to
FIG. 12 . An axial fan A according to the present preferred embodiment is similar to the axial fan A according to the first preferred embodiment described above except that thethird slit group 113 is eliminated, leaving only the first andsecond slit groups slit groups slits - While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
Claims (10)
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JP2010-171407 | 2010-07-30 | ||
JP2010171407A JP5636792B2 (en) | 2010-07-30 | 2010-07-30 | Axial fan and electronic device equipped with the same |
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US8953315B2 US8953315B2 (en) | 2015-02-10 |
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US13/185,523 Active 2032-10-23 US8953315B2 (en) | 2010-07-30 | 2011-07-19 | Axial fan and electronic device including the same |
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US20140036439A1 (en) * | 2012-08-03 | 2014-02-06 | Hon Hai Precision Industry Co., Ltd. | Electronic device |
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US20180119635A1 (en) * | 2015-04-17 | 2018-05-03 | Henry Maurice Wandrie, III | Piston with multi-arcuate cross-section and lubricant exhaust aperture |
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USD777313S1 (en) * | 2015-11-06 | 2017-01-24 | Pelonis Technologies, Inc. | Blower housing |
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US11131324B2 (en) | 2016-09-02 | 2021-09-28 | Hewlett-Packard Development Company, L.P. | Fan housing for reduced noise |
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US11396880B2 (en) * | 2018-11-08 | 2022-07-26 | Nidec Corporation | Inline axial flow fan |
Also Published As
Publication number | Publication date |
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JP2012031772A (en) | 2012-02-16 |
CN102345643B (en) | 2014-04-02 |
CN102345643A (en) | 2012-02-08 |
US8953315B2 (en) | 2015-02-10 |
JP5636792B2 (en) | 2014-12-10 |
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